Salmon Survival

Ocean conditions play a key role in the health of Northwest salmon runs, and scientists at OSU’s Hatfield Marine Science Center are trying to pinpoint why. Clearly there are more salmon during cold-water regimes, when strong and persistent upwelling fertilizes the marine food web.

Bill Peterson, a federal biologist at the Hatfield Center, says one reason may be the appearance of northern copepod species during these cold-water events. Copepods, a type of zooplankton, are a primary prey for herring, anchovies and other salmon staples. Peterson says cold-water copepod species are lipid-rich, and those extra nutrients are important to salmon survival.

“Only the healthy salmon can survive that first winter at sea, and the extra fats provided by northern copepods may make the difference,” Peterson adds. Peterson has a courtesy appointment with OSU’s College of Oceanic and Atmospheric Sciences (COAS).

OSU geneticist Michael Banks of the Coastal Oregon Marine Experiment Station is leading a project to identify the origins of salmon caught off the Oregon coast. In 2006, he and colleagues worked with commercial fishermen to study genetic material from more than 2,000 Chinook salmon. Pinpointing the river basin of origin with high accuracy, the scientists validated their results by linking genetic identification with coded tags in all cases.

“Now that we can identify where the salmon are from, the next step is to learn how the distribution of fish is related to oceanographic data,” Banks says.

Banks and colleagues from COAS, Sea Grant and the National Oceanic and Atmospheric Administration are evaluating data (temperature, salinity, dissolved oxygen and chlorophyll) from OSU undersea gliders. They hope to learn how salmon are distributed throughout the ocean so that fishery managers can avoid shutting down the entire region to protect a single run of fish, like those from the Klamath River.

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